A Plant genus of the Family Alismataceae. The Flowers have 3 green sepals, 3 yellow and White petals, 6 stamens, and several pistils. Members contain TRITERPENES and SESQUITERPENES. Alisma is a component of tokishakuyakusan. Some species in this genus are called Water Plantain which is also a common name for other Alismataceae Plants.